Iron deficiency anemia and milder sub-clinical iron deficiency, resulting in reduced or nonexistent iron stores, and major world-wide nutritional problems among young children and women of reproductive age. Because of this, influences of iron status on immune function assume considerable importance in maintaining a healthy disease-free state. The existing literature relating iron status to infectious disease is contradictory with both beneficial and detrimental effects of iron on the susceptibility to infection reported. The proposed research involves a clearly defined experimental model to study the effects of iron nutriture on the development of immunocompetence in the rat, independent of concurrent nutritional health, environmental, and parasitic problems. The proposed research hypotheses include: 1. Iron nutrition influences components of non-specific immunity including circulating immunoproteins and secretory proteins which form the first line of defense in the host response. 2. The quality of iron nutriture during reproduction influences the development of the immune response in the maternal and neonatal organisms. In vitro indicators of immunocompetence which will be measured in varying states of iron nutriture include: secretory proteins, circulating immunoproteins, antibody producing capacity, and bactericidal activity of neutrophils. Results of this research defining the role of iron in disease resistance may be used to formulate health policies and develop techniques for treating and preventive clinical and non-clinical iron deficiency and also infectious diseases.